CRISPR-Cas12a-based aptasensor for sensitive and selective FB1 detection

Fumonisin B1 (FB1) is a common mycotoxin found in agricultural products. Therefore, establishing rapid detection methods is an important means to prevent the harm of FB1. This study was based on the clustered, regularly spaced short palindromic repeats (CRISPR)-Cas12a system with the introduction of aptamer F10. This study aimed to design CRISPR RNA (crRNA) to specifically recognize the aptamer F10, which formed the competitive relationship between the target molecule and crRNA for nucleic acid aptamer. Finally, a new type of biosensor was established using the trans-cleavage activity of Cas12a protein and amplifying the signal with a fluorescent probe. This study observed a linear relationship of FB1 concentrations in the range of 25–500 nM. The standard curve was y = −0.2586 × x + 775.3, R2 = 0.9922, and the limit of detection (LOD) was 16.84 nM. The recovery of the maize sample was 92.2–101.93% and 92.24–103.96%. The total assay time was 40 min. The biosensor showed high specificity and sensitivity for FB1 after the introduction of the aptamer F10, and the workflow was simple, convenient, and fast, which was suitable for point-of-care (POC) detection in the field. Our designed biosensor validated the principle of detecting small molecules using CRISPR-Cas12a systems, further facilitating its application in the diagnostic field.